1. Field of the Invention
The present invention relates to a photosensitive material processing rack used for developing a photosensitive material such as a photo film, a color paper, and a photosensitive material processing apparatus provided with the rack.
2. Background Arts
A photosensitive material processing apparatus used in a photo-lab and the like is composed of feed rollers for feeding an exposed photosensitive material, and plural processing tanks containing various types of processing solution used for color development, bleach fixation, rinse, stabilization and the like. The photosensitive material fed by the feed rollers is subject to the processes of development, fixation, and rinse while sequentially passing through the various types of processing solution contained in the processing tanks.
As disclosed in Japanese Patent Laid-Open Publication No. 11-352656, for example, a photosensitive material processing rack, which is hung on the upper end of the processing tank, holds the feed rollers. In addition to the feed rollers, the rack has a pair of sidewalls for holding the ends of the feed rollers, and drive shafts for driving the feed rollers.
Since the processing rack is so designed as to have heavier weight than buoyant force exerted on the processing rack soaked in the processing solution, the processing rack is fixed on the processing tank without floating. The size of the processing rack is larger than the volume of the processing solution necessary for processing the photosensitive material. In view of reducing processing cost, the inside of the processing rack is made hollow to increase the volume thereof, for the purpose of filling the processing tank with a small amount of processing solution. Increase in the volume brings increase in the buoyant force exerted on the processing rack, so that the processing rack is unstably fitted into the processing tank.
When the processing rack is unstable, the processing rack may be shifted from a proper position or may be detached from the processing tank due to the operational vibration caused by the processing apparatus, torque from a drive source for driving the feed rollers and the like. In such a case, the misalignment of a feeding path for feeding the photosensitive material causes poor feeding and clogging of the photosensitive material, so that the photosensitive material tends to be bent or damaged. To stably fix the processing rack in the processing tank, it is considerable to provide a fixing member. In this case, however, increase in the number of parts causes increase in manufacturing cost of the processing apparatus.
An object of the present invention is to provide a photosensitive material processing apparatus, at low cost, in which a photosensitive material processing rack is easily and stably fixed in a processing tank.
To achieve the above object, a photosensitive material processing rack according to the present invention comprises a housing, a feed roller pair provided in the housing, and a weight detachably loaded into and/or onto the housing. The feed roller pair feeds a photosensitive material along a feeding path in the processing tank. The weight stably fixes the rack in the processing tank against buoyant force exerted on the rack in the processing solution.
In the housing, at least one hollow portion may be formed. In this case, the weight is loaded into the hollow portion.
The photosensitive material processing rack satisfies the following formulas:
xcex2 greater than (Vxc3x97xcex1xe2x88x92W)/X
Vxc3x97xcex1 greater than W
wherein, W is the weight of the rack without the weight, V is the volume of apart of the rack soaked in the processing solution, xcex1 is the specific gravity of the processing solution, xcex2 is the specific gravity of the weight, and X is the volume of the weight.
The photosensitive material processing rack may further satisfies the following formula:
Xxe2x89xa6v
wherein, v is the volume of a hollow portion formed inside the housing.
According to the present invention, since the photosensitive material processing rack has enough weight by loading weights, it is possible to stably fix the processing rack in the processing tank. When the processing rack is detached from the processing tank, the weights are removed to lighten the weight of the processing rack, so that workability is improved.